CAIRO, Sept 13 (Reuters) - Egyptian state television accusedPalestinian Hamas on Thursday of training Egyptian Islamists inhow to carry out bombings, putting more pressure on the MuslimBrotherhood, ally of Hamas.

In neighbouring Gaza, the ruling Hamas Islamists stronglydenied the allegations.

Egypt has faced turmoil since the army forced theBrotherhood's Mohamed Mursi from the presidency in July. A weekago, the interior minister survived an assassination attempt inCairo, amid fears the country could face an Islamist insurgency.

The allegations that Hamas has been training Egyptianmilitants could lead the military-backed authorities to escalatetheir crackdown on the Brotherhood.

"Security authorities have learned that the military wing ofthe Hamas movement trained several people to undertakecar-bombing operations and trained various others to makeexplosives," said a presenter on state television.

"The military wing of the Hamas movement provided variousSalafi jihadists and also other religious currents with 400landmines. The security apparatus documented this and they willbe arrested."

Fawzi Barhoum, spokesman for the Islamist group thatcontrols the Gaza Strip, said of the report, "This is completelyincorrect".

It was an "attempt to demonise Hamas", he added.

Hamas is an offshoot of the Muslim Brotherhood, which hasbeen on the defensive since Mursi was ousted from the presidencyfollowing mass protests. He had alienated millions of Egyptiansby giving himself sweeping powers and mismanaging the economy.

The main state paper, al-Ahram, cited high-ranking securitysources as saying Hamas was also involved in the failedassassination attempt against the interior minister earlier thismonth. It did not elaborate or name the sources.

The army-backed government in Egypt has tightened control ofcrossings from the Sinai peninsula into Gaza, which Egypt ruledfrom 1948 to 1967, and continued assaults on militants in Sinai.

Egypt's closure of cross-border smuggling tunnels used tomove weapons and goods into the Gaza Strip has dealt a majorblow to the Palestinian group.

Hamas has recently tried to lower tension with Egypt,ordering Muslim preachers to mute their criticism of Cairo.

Gaza preachers, in fiery sermons, have accused Egypt's armychief, General Abdel Fattah al-Sisi, of waging war on Islam.Egyptian army officials have accused Hamas of interfering inEgyptian affairs and suggested Palestinians were helpingIslamist militants in Sinai, which borders Gaza and Israel.

At Gaza street rallies, Hamas fighters have flashed afour-finger salute - a show of support for Mursi.

His ousting was seen as a setback for Hamas, and came as thegroup's ties with traditional allies Iran and the LebaneseHezbollah party have also suffered over its siding with rebelsbattling Syrian President Bashar al-Assad.

Security sources said the former chief of staff under Mursi,Mohamed Rifaa el-Tahtawy, was detained on Thursday on charges ofespionage. He had been detained in August over accusations ofinciting the detention, torture and interrogation of protestersin 2012, but was released on Tuesday.

STATE OF EMERGENCY

The Sinai-based group Ansar Bayt al-Maqdis has claimedresponsibility for the suicide bombing aimed at InteriorMinister Mohamed Ibrahim. It promised more attacks in revengefor the crackdown on Egypt's Islamists, raising fears thatmilitant violence in Sinai could spread across the country.

Another group called Jund al-Islam (Soldiers of Islam) putout a statement on a Facebook page claiming responsibility fortwo attacks on the Egyptian army, including the car bomb thatexploded at an intelligence facility in Egypt's Sinai onWednesday, killing four people.

Aside from unrest in the Sinai, Egypt's government says theBrotherhood itself also poses a security threat, accusing it ofcarrying out terrorist acts.

Security forces killed hundreds of members during a raid onpro-Mursi protest camps in Cairo on Aug. 14 and then arrestedtop Brotherhood leaders accused of inciting violence.

There are no signs the pressure on Islamists will ease.

Egypt extended a state of emergency for two months onThursday as authorities expressed growing concern over militantviolence. It also has an overnight curfew in place.

The government originally announced a one-month state ofemergency on Aug. 14 and Thursday's announcement extended theorder, which covers the whole country, to mid-November.

The Muslim Brotherhood has accused the government ofrehabilitating the older, autocratic order under President HosniMubarak for 30 years and catering to military officials.

An Egyptian court on Thursday acquitted all 14 defendants,including policemen, accused of killing 17 protesters during thebloodiest day of a revolt that toppled Mubarak over two yearsago, judicial sources said.

The deaths in Suez City triggered violence across Egypt onwhat was later called "The Friday of Rage" - Jan. 28, 2011 -that fuelled an 18-day uprising against Mubarak, who had ruledEgypt for 30 years.

The case is the latest in a series in which Mubarak-eraofficials were either acquitted or given light sentences,raising frustrations among opponents of the government and theformer Mubarak administration.